Method of and means for testing staybolts



1937. G. R. GREENSLADE METHOD OF AND MEANS FOR TESTING STAYBOLT$ Filed Sept. 4, 1934 3 Sheets-Sheet l Dec. 28, 1937. e. R. GREENSLADE METHOD OF AND MEANS FOR TESTING STAYBOLTS Filed Sept. 4, 1954 3 Sheets-Sheet 2 FIG. 3 28 FIG.4.

2 1937. G. R. GREENSLADE' 2,103,256

METHOD OF AND MEANS FOR TESTING STAYBOLTS' Filed Sept. 4, 1954 I 5 Sheets-Sheet 3 F1 6.. 5

FIG 6 v 17 2s i\\\ 41 UNHTE STATES PATENT OFFlC METHOD OF AND MEANS FOR TESTING .STAYBOLTS Grover R. Greenslade, Scott Township, Allegheny County, Pa., assignor to Pittsburgh Dry Stencil Company, a corporation of Pennsylvania Application September4, 1934, Serial No. 742,656

Claims. (01. 1'75-183) This invention pertains to new and improved telltale hole of a staybolt, indicates directly methods of testing staybolts and to instruments whether or not the bolt is fractured and at the to be used in connection with the said methods of same time in case of fracture, its location along testing. More particularly the invention relates the length of the bolt. 1

5 to means'for testing so-called telltale staybolts Other devices have been proposed to accomof either the flexible or rigid type. plish the above-mentioned purpose, involving l-leretofore, boiler staybolts and in particular complex circuits, sliding contacts, etc., whichenlocomotive staybolts have been tested by various climber the process of testing considerably and 1 means. Flexible staybolts wereoriginally tested render the carryingout'of the test difiicult'and method of testing was very expensive and unnew and simplifiedelectrical testing unit'is procertain. It was expensive because it required the vided which requires no external contacts, or removal of all fittingsthe jacket, lagging, and electrical leads of any'kind for connecting it to even the caps which form the closures over the other means or appliances. The instrument is headed ends of the staybolts. simple of operation and results of tests are quick- 15 The hammer test was accomplished by taply obtained therewith. ping the heads of the staybolts after the removal The apparatus used in the present invention of all of the above-mentioned equipment so that and the method of performing the test can be the operator might judge from the sound whether easily understood by referring to the accompanyor not the bolts were broken. By this method, ing drawings and to the detailed description proit was impossible for even an experienced operavided below.

tor to locate with certainty all of the broken bolts In the drawings: in a boiler. Fig. l is an elevational view of a testing imple- A later and improved method of testing flexible ment; 7 v 25 staybolts by means of a so-called electrical con- Fig. 2 isan enlarged'longitudinal sectional view tact tester, is disclosed in Patent #1581728, is of the pilot or exploring end'of the testing imsued Dec. 29, 1925 to G. R. Greenslade. The plement shown in Fig. 1;

invention described in said patent makes use of Figs. 2a and 2b are enlarged longitudinal sec an electrical implement in conjunction with a tional views of modified forms of the pilot or by what is known as the hammer test. This uncertain. In'the present invention, however, a Q

telltale hole in a staybolt, the said hole extendexploring end of the testing implement; g

ing from the fire sheet end of the staybolt into Fig. 3 is a view illustrating one manner in but not through the headed end thereof. The which a testing implement is employed in the electrical contact tester in itself is used to detertelltale hole of a flexible staybolt installation, mine whether or not the telltale hole is open the staybolt and portions of the inner and outer throughout its entire length by making contact sheets of a boiler being shown in section; i Y 5- at the original closed end of the hole within the Fig. 4 is a view, partly in section, of an electrohead of the staybolt, or in case of any clogging magnet used in connection withthe test for of the hole, indicating that the tester has not energizing the boiler and staybolts as hereinafter reached the said original closed end. In case described; a

the electrical testing implement indicates that Fig. 5 is a view illustrating the use of a testing 40 the latter condition exists, the telltale hole is implement in connection with a flexible staybolt then cleaned out by means of a drill until the assemblage in which the telltale hole extends all instrument indicates that the hole is clean and of the Way through the bolt and is accessible from therefore functioning throughout the entire either end; and 45, lengtl Fig. 6 is a View illustrating the application of I The actual condition of the bolt itself is then a modified form of the invention to the testing determined by applying to the boiler the hydroof staybolts, the staybolt shown in section being static test which indicates any broken bolts by of the ri yp ving a ll hole ten in leakage of water through the telltale hole and longitudinally all of the way through the bolt.

into the firebox. It is evident therefore that the Although I have illustrated in Figs. 3, 5 and 6 50 said electrical contact tester does not test in a the use of my invention in testing but few of the direct manner the condition of a bolt but rather types of telltale staybolts which have been dothat of the telltale hole. vised, it is to be understood that the invention It is the purpose of the present invention to may be employed in the testing of any or all of provide a tester which, when inserted into the such telltale staybolts. 7 55" The term telltale staybolts as used in the specification and claims for my invention signifies and includes all types of staybolts that have a passage extending longitudinally, partly or entirely through the staybolt.

In the description that follows, similar parts of the apparatus shown in the various figures are designated by the same numeral.

Referring to the essential parts of the testing implement and equipment involved as shown in the various figures, we have in Fig. 1, an exploring rod I, made of hollow non-magnetic tubing such as brass, a pilot tip 2 at the extreme end of said exploring rod l, a handle 3 to which the exploring rod l is attached, and an electrical mil-ammeter 4 mounted conveniently on the handle 3.

Fig. 2 illustrates the electrical and magnetic parts which are contained in the exploring rod I As may be seen from the figure, the pilot tip 2 is an extension of one end of a spool-shaped member that lodges Within the end of the exploring rod I. The narrow portion 5 (hereinafter designated as a core) of the spool-shaped member serves as a core for a coil 6 of insulated copper or other suitable wire that occupies the annular space between the axially disposed portion 5 of the spool and the inner wall of the tubular exploring rod I. Thespool-shaped member including the pilot tip 2 and the core 5 is made of ferrous or other magnetic metal or alloy preferably of high magnetic permeability andlow retentivity.

The end portions I and 8 of the coil of wire 6 extend through small drilled holes 9 and I0 re-v spectively in the inner head, end ll of the spoolshaped member. The. ends of the Wires 1 and 8 are connected by means of soldered joints [2 and I3 to heavy lead Wires [4 and I5. which extend through the length of the tubular exploring rod 1 to the terminals of the electrical mil-ammeter 4 mentioned, in connection, with Fig. 1. be seen that in this manner, the electrical circuit of the meter and coil is completed.

Referring to Fig. 3-, in. the assemblage shown,

l6 represents a portion of the inner or firebox,

sheet of a locomotive boiler. Extending between the fire sheet [.6 and the wrapper sheet, I] of the locomotive boiler, is a flexible, staybolt l8. having a telltale hole l9, extending from the fire sheet end of the bolt into but not through theheaded end 26. The headed end 20.01; the bolt lilisinclosed by a cap 2 which hasa weld 22' which secures the cap 2] to the wrapper. sheet ll". and prevents the. escape of steam or water. from the boiler.

The, wrapper sheet .l'l has a counterbore 23 adapted to form a seat. for the headed end 20 of the flexible staybolt I8;. The fire'sheet end of the flexible staybolt I8,has,.a thread 24;.bymeans of which thestaybolt is. screwed through the fire.

sheet 3. After the flexible staybolt I85 is screwed inas described, it is rivetedover. asshown at 25. The bolt l8 as shown in the figure. has. a

fracture 26 extending. laterally part. of the way, through thebolt. Theexploring rod l, for pur.-. poses of illustrating the heavy electrical leads l4:

and I5, is shown broken at 21, and. is furthermore illustrated as havingibeen inserted part. of the way into the telltale hole. IQ. of thefiexible.

staybolt 18 so that the pilot, tip 2 has passed somewhat farther into the, telltale hole than the position of the fracture. 26. The significance of this particular location of the pilot'tip 2v during the insertion of theexploring rod I will be appreciated when .the method -of,locating a fracture is explained.

An electromagnet is shown,with. the.free end;

It may,

. coil 6 in the exploring. rod 1.

28 of its core placed in contact with the cap 2|. The electromagnet is shown in section in Fig. 4 in which 29 represents the core of the magnet made of ferrous metal or alloy and preferably laminated to prevent eddy currents. Retaining discs 30 and 3| and a cylindrical sheet 32 serve to enclose the annular space which contains a. magnetizing coil 33 composed of many turns of insulated copper wire. The leads 34 and 35 of the magnetizing coil 33 pass out from the annular space through the holes 36 and 31 respectively in the retaining disc3l so that they may be connected to any convenient power line such as 110 or 220 volts of alternating current. If desired a handle 38 maybe provided as ameans for holding the elect-romagnet in position as shown in Fig. 3.

The method of testing the telltale flexible staybolts of a locomotive boiler as employed by this invention is as follows:-

The energizing electromagnet described above is connected to an A. C. power line as explained and is then placed so that the pole 28 is in contact with the wrapper sheet 11 of the boiler or in contact with a cap. 2| which may be in the vicinity of a group of telltale staybolts which are to be tested. When in this position and energized by the power circuit, an alternating magnetic field is set up in all parts of the ferrous structureadjacent to the. point ofcontact, of pole- 28 of the electromagnet. Each staybolt in the vicinity polarity and the lines of magnetic force extend along these bolts substantially parallel to their axes. If therefore the exploring rod lis thrust into the telltale hole [9 of the staybolt l8 and is caused. by the operatorto move so that. the pilot tip 2 of the exploring rod l traversesthe length of the telltale hole from its opening at the fire sheet end of the staybolt l8 to the termination of the telltale hole Ill-withinthe headed end 2001 the staybolt l8, some of the magnetic lines of force passing through the bolts are diverted from their Q thereforeis magnetized with a fiux of alternating axial direction and pass-through the core;5 of the In accordance with the laws of, electromagnetic induction, these diverted alternating lines. of magnetic force which, pass through the core 5 of the coil Ginduce in the coil 6 an alternating electric current, the presence of which is indicated by; the mil amn eter 4-. If no fracture is presentin. the staybolt the deflection of the needle of themil-ammeterA remains substantially constant as the pilot tip 2 ismoved along the telltale hole by the operator asdescribed above.

If, however, the bolt lfizis. fractured. asshown:

at 26, the ferrouscrosssection of thelstaybolt. I81

at right anglesto the axis of? the bolt attheposi. tion of the fracture is diminished; and, the area; of solid metal availablafor containingfthealternating lines. of force which extend'through the: bolt is diminished, with the result that when-the core 5zisin such a positionasitdstand orgbridge; over the fracture 26a relatively. large number of: lines of magnetic force within the body of the bolt are diverted was to pass through. the pilot tip 2 and through the core 5'. Insucha-positiom therefore thealternating current generatedin; the coil 6 of the testing implement is. greatly augmented and; the needle of themil ammeter; 4 therefore indicates a 11111011113186! current.-, The, position of.the.exploring rod-;l illustrated; in Fig; 3 is approximately such aposition.

It; may be seen from this that,;.the: Operator while, ob rvin ..the needle: Qfth i. mi -ammeten; 75-;

4 of the testing implement as he moves the exploring rod along the telltale hole H? of the staybolt 18 can determine and locate a fracture by the sudden increase of electrical current indicated by the increase in deflection of the needle of the mil-ammeter 4.

A valuable feature of this invention as already pointed out is that the testing implement enables the operator to determine directly a fracture in the bolt. An added advantage of this invention is that it is not necessary that the bolt be broken completely across or even that the fracture has extended sufiiciently far to reach the telltale hole of a staybolt inasmuch as a relatively small fracture of the staybolt will increase the number of lines of the alternating magnetic field which are diverted so as to pass through the pilot tip at the end of an exploring rod and through the core of the coil within an exploring rod. An experienced operator is therefore able to locate readily a fracture in a staybolt and is able to tell approximately the extent of such fracture by the relative-increase of the deflection of the needle of the mil-ammeter 4.

A still further advantage of this invention is that it also provides a means of ascertaining whether or not the telltale hole is open and unobstructed throughout its entire length. The latter advantage is made evident by the following explanation:

In Fig. 3 the exploring rod l is shown only partly inserted in the telltale hole I9 of the staybolt l8 so that the pilot tip 2 at the end of the said exploring rod l is located at a considerable distance from the closed end 39 of the telltale hole l9 within the head 20 of the staybolt I8. If however, the exploring rod l is thrust into the telltale hole I9 until the pilot tip 2 makes contact with said inner end 39 of the telltale hole such contact at this point will cause an unusually large amount of the magnetic flux within the boundary of the staybolt to be deflected so as to pass into the pilot tip 2 and through the core (shown in enlarged section Fig. 2).

While the above described contact exists, an unusually large electromotive force is generated in the coil 6 (also shown in Fig. 2) resulting in a larger electrical current through the mil-ammeter 4. The unusually large deflection of the needle of the mil-ammeter. makes known to an operator that the pilot tip has reached the original closed end of the telltale hole of the bolt within the head thereof. It is evident from this that an operator, experienced in the practice of testing staybolts by means of the above-described implement and appurtenances, is able to determine not only the condition of the bolt as regards fracture thereof, by following the procedure hereinbefore described, but also the condition of the telltale hole.

For example, if the testing implement, when thrust into the telltale hole as far as possible, does not give indication of having reached the original closed end of the hole, it is evident that some obstruction such as rust, corrosion or scale is present in a portion of the hole and that this must be removed, by means of a drill, or other suitable implement before the test may be completed. The latter is necessary since it is possible that a fracture may exist in the bolt beyond the. position of stoppage. If however the hole is cleaned out, and the testing implement when fully inserted indicates that the pilot has reached the original closed end of the hole, then the entire lengthof the telltale hole may be ex:- plored and any existing fracture located.

In Fig. 5, a staybolt 40 is shown provided. with a telltale hole 48 accessible from either end, the

cap 42 at the head end being provided with-an opening 43 in line with the said telltale hole 4|. The staybolt is shown with a fracture 44 extending laterally all of the way through. The ex.- ploring rod l is shown in its approximate position for locating the fracture. Althoughthe exploring rod is shown inserted in the telltale hole from the fire sheet end of the staybolt, it is readily seen that the test can be. carried on just as effectively by inserting the exploring rod through the head end of the staybolt. In Fig. 6, a staybolt 45 of the rigid type having a telltale hole 41 extending all of the way through it, is shown. The testing implement difiers from the implement shown in Fig. 1 and succeeding figures in that the handle. 48 of the exploring rod I does not have an ammeter attached thereto. The wires, 49 and 50 extend from tube I. Inthe form shown in Fig. 2b, the pilot tip is shown entirely embedded within the end of the tube l. The outer end 53 of the spoolshaped member on which the coil 6 is wound, is exposed and is flush with the end of the tube 1.

It is to be understood that the invention described and illustrated herein covers broadly the application of principles which have been ex plained, and that various modifications may be made within the scope of the invention, including, for instance, the following:-

Current indicating devices other than the milammeter mentioned herein may be employed and such devices may or may not be attached to the handle of the testing implement.

Whereas I'have illustrated a particular means of magnetically energizing the system by employing an electromagnet as described, other means of energizing the system may be used. Furthermore, it is not necessary that the energizing means he applied at the wrapper sheet end of the staybolt but may be applied in the vicinity of the fire sheet end. If desired, a solenoid may be used instead of an electromagnet. 3

Whereas I have described the use of the inven tion in connection with an alternating current,'it

may equally well be employed by the use of direct current in conjunction with an interrupter, or by 1 means of the current induced in the testing implement circuit by the opening or closing of a direct current energizing circuit. Still other modifications than the above may be employed in the utilization of my invention.

The following copending applications include methods of testing telltale staybolts and telltale ,2, 10.352 5&6

the said apparatus including a testing implement provided with an attenuated portion movable within the telltale hole of the bolt for determining the condition of the bolt by magnetic exploration of'the telltale hole thereof.

2. A testing implement for telltale staybolts, the said implement comprising a tubular member adapted for insertion in the telltale hole of a staybolt, an electromagnetic coil within the said member, a handle for the said member and an .elec- 'trical meter in the circuit of the said electromagnetic coil the said coil being movable with.

respect to a staybolt while exploring a magnetic field in the bolt throughout every breakable portion thereof.

3. In apparatus for testing a telltale. staybolt assemblage comprising a staybolt having a telltale hole the said staybolt engaging theinner and outer plates of a boiler; an electromagnet for temporary association with the stayboltand an electromagnetic'coil constructed to move within the telltale hole of said staybolt to denote by exploration of magnetic flux from the'said magnet the condition of the bolt throughout every breakable portion thereof. 4. Apparatus for testing a telltale staybolt having an alternating current electromagnet associated therewith whereby the bolt is magnetized substantially longitudinally with an alternating flux, a testing implement comprising a rod and a handle,. an insulated coil within the rod, an electrical meter attached to the said handle, the said meter being connected in the circuit of the coil, the said rod being insertable in the telltale hole of the staybolt and movable therein while determining the condition of the bolt by measuring the intensity of the magnetic flux within the telltale hole of the bolt throughout the entire length of the said telltale hole.

5. In apparatus for testing a staybolt assemblage, including a bolt having a telltale hole said bolt .engaging the inner and outer sheets of a boiler, an electromagnet temporarily associated with the staybolt, an electromagnetic coil constructed to move within and along the entire length of the telltale hole of the staybolt to denote directly by exploration of magnetic flux from the said magnet the condition of the boltand of the V telltale hole.

adapted to be set up by induction, and noting ,anotherbolt.

connected to the said magnetic exploring coil,

the .saidimplement being movable with respect to a staybolt adapted to explore a magnetic field in the. bolt in spaced relation thereto throughout every breakable portion thereof and while the staybolt is in ,place ina boiler whereby the presence or absence of defects is determined directly from the bolt tested and without compari-' son with another bolt.

8. A testing implement for determining the condition of telltale staybolts, the said implement including means adapted for magnetic exploration of the telltale hole of the said staybolts in spaced relation thereto throughout 'the entire length of the said telltale. hole while the staybolts are in place in a boiler, whereby the presence or absence of defects is determined directly from the bolt testedand without comparison with 9. A testing implement for use with staybolts having telltale holes, the said implement being adapted. to indicate directly the condition of the staybolts and of the telltale holes thereof and thesaid implement including a single testing member movable with respect to a staybolt while the staybolt is in place in a boiler and adapted 7 means in which electric currents are established,

andpassing the said means through the entire length of the telltale hole, and noting by electrical indicating means during the exploration of the telltale hole the presence or absence of fractures in the staybolt and of non-conducting accumulations in the telltale hole. 7

' GROVER R. GREENSLADE. 

